This document discusses symbols used in interior design drawings. Doors and windows are represented by simple symbols to indicate features like if they open inward or outward. Line thickness in drawings represents different elements, with base lines showing edges and thin lines showing non-structural details. Section lines distinguish walls from elements above in a plan view. Stairs are shown with banisters as two lines and an arrow to indicate direction. Elevations provide straight-on views of walls. Measurements are taken on site and translated to preliminary drawings before finalizing plans and elevations.